261 lines
6.5 KiB
C
261 lines
6.5 KiB
C
/*
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* Support for the OLPC DCON and OLPC EC access
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*
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* Copyright © 2006 Advanced Micro Devices, Inc.
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* Copyright © 2007-2008 Andres Salomon <dilinger@debian.org>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*/
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#include <linux/kernel.h>
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/delay.h>
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#include <linux/spinlock.h>
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#include <linux/io.h>
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#include <linux/string.h>
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#include <asm/geode.h>
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#include <asm/olpc.h>
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#ifdef CONFIG_OPEN_FIRMWARE
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#include <asm/ofw.h>
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#endif
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struct olpc_platform_t olpc_platform_info;
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EXPORT_SYMBOL_GPL(olpc_platform_info);
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static DEFINE_SPINLOCK(ec_lock);
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/* what the timeout *should* be (in ms) */
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#define EC_BASE_TIMEOUT 20
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/* the timeout that bugs in the EC might force us to actually use */
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static int ec_timeout = EC_BASE_TIMEOUT;
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static int __init olpc_ec_timeout_set(char *str)
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{
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if (get_option(&str, &ec_timeout) != 1) {
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ec_timeout = EC_BASE_TIMEOUT;
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printk(KERN_ERR "olpc-ec: invalid argument to "
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"'olpc_ec_timeout=', ignoring!\n");
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}
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printk(KERN_DEBUG "olpc-ec: using %d ms delay for EC commands.\n",
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ec_timeout);
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return 1;
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}
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__setup("olpc_ec_timeout=", olpc_ec_timeout_set);
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/*
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* These {i,o}bf_status functions return whether the buffers are full or not.
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*/
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static inline unsigned int ibf_status(unsigned int port)
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{
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return !!(inb(port) & 0x02);
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}
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static inline unsigned int obf_status(unsigned int port)
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{
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return inb(port) & 0x01;
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}
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#define wait_on_ibf(p, d) __wait_on_ibf(__LINE__, (p), (d))
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static int __wait_on_ibf(unsigned int line, unsigned int port, int desired)
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{
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unsigned int timeo;
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int state = ibf_status(port);
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for (timeo = ec_timeout; state != desired && timeo; timeo--) {
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mdelay(1);
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state = ibf_status(port);
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}
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if ((state == desired) && (ec_timeout > EC_BASE_TIMEOUT) &&
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timeo < (ec_timeout - EC_BASE_TIMEOUT)) {
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printk(KERN_WARNING "olpc-ec: %d: waited %u ms for IBF!\n",
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line, ec_timeout - timeo);
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}
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return !(state == desired);
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}
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#define wait_on_obf(p, d) __wait_on_obf(__LINE__, (p), (d))
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static int __wait_on_obf(unsigned int line, unsigned int port, int desired)
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{
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unsigned int timeo;
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int state = obf_status(port);
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for (timeo = ec_timeout; state != desired && timeo; timeo--) {
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mdelay(1);
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state = obf_status(port);
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}
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if ((state == desired) && (ec_timeout > EC_BASE_TIMEOUT) &&
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timeo < (ec_timeout - EC_BASE_TIMEOUT)) {
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printk(KERN_WARNING "olpc-ec: %d: waited %u ms for OBF!\n",
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line, ec_timeout - timeo);
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}
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return !(state == desired);
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}
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/*
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* This allows the kernel to run Embedded Controller commands. The EC is
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* documented at <http://wiki.laptop.org/go/Embedded_controller>, and the
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* available EC commands are here:
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* <http://wiki.laptop.org/go/Ec_specification>. Unfortunately, while
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* OpenFirmware's source is available, the EC's is not.
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*/
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int olpc_ec_cmd(unsigned char cmd, unsigned char *inbuf, size_t inlen,
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unsigned char *outbuf, size_t outlen)
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{
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unsigned long flags;
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int ret = -EIO;
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int i;
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spin_lock_irqsave(&ec_lock, flags);
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/* Clear OBF */
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for (i = 0; i < 10 && (obf_status(0x6c) == 1); i++)
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inb(0x68);
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if (i == 10) {
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printk(KERN_ERR "olpc-ec: timeout while attempting to "
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"clear OBF flag!\n");
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goto err;
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}
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if (wait_on_ibf(0x6c, 0)) {
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printk(KERN_ERR "olpc-ec: timeout waiting for EC to "
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"quiesce!\n");
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goto err;
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}
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restart:
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/*
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* Note that if we time out during any IBF checks, that's a failure;
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* we have to return. There's no way for the kernel to clear that.
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*
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* If we time out during an OBF check, we can restart the command;
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* reissuing it will clear the OBF flag, and we should be alright.
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* The OBF flag will sometimes misbehave due to what we believe
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* is a hardware quirk..
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*/
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printk(KERN_DEBUG "olpc-ec: running cmd 0x%x\n", cmd);
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outb(cmd, 0x6c);
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if (wait_on_ibf(0x6c, 0)) {
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printk(KERN_ERR "olpc-ec: timeout waiting for EC to read "
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"command!\n");
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goto err;
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}
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if (inbuf && inlen) {
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/* write data to EC */
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for (i = 0; i < inlen; i++) {
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if (wait_on_ibf(0x6c, 0)) {
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printk(KERN_ERR "olpc-ec: timeout waiting for"
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" EC accept data!\n");
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goto err;
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}
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printk(KERN_DEBUG "olpc-ec: sending cmd arg 0x%x\n",
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inbuf[i]);
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outb(inbuf[i], 0x68);
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}
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}
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if (outbuf && outlen) {
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/* read data from EC */
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for (i = 0; i < outlen; i++) {
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if (wait_on_obf(0x6c, 1)) {
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printk(KERN_ERR "olpc-ec: timeout waiting for"
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" EC to provide data!\n");
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goto restart;
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}
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outbuf[i] = inb(0x68);
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printk(KERN_DEBUG "olpc-ec: received 0x%x\n",
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outbuf[i]);
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}
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}
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ret = 0;
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err:
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spin_unlock_irqrestore(&ec_lock, flags);
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return ret;
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}
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EXPORT_SYMBOL_GPL(olpc_ec_cmd);
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#ifdef CONFIG_OPEN_FIRMWARE
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static void __init platform_detect(void)
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{
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size_t propsize;
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__be32 rev;
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if (ofw("getprop", 4, 1, NULL, "board-revision-int", &rev, 4,
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&propsize) || propsize != 4) {
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printk(KERN_ERR "ofw: getprop call failed!\n");
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rev = cpu_to_be32(0);
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}
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olpc_platform_info.boardrev = be32_to_cpu(rev);
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}
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#else
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static void __init platform_detect(void)
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{
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/* stopgap until OFW support is added to the kernel */
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olpc_platform_info.boardrev = 0xc2;
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}
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#endif
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static int __init olpc_init(void)
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{
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unsigned char *romsig;
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/* The ioremap check is dangerous; limit what we run it on */
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if (!is_geode() || geode_has_vsa2())
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return 0;
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spin_lock_init(&ec_lock);
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romsig = ioremap(0xffffffc0, 16);
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if (!romsig)
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return 0;
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if (strncmp(romsig, "CL1 Q", 7))
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goto unmap;
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if (strncmp(romsig+6, romsig+13, 3)) {
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printk(KERN_INFO "OLPC BIOS signature looks invalid. "
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"Assuming not OLPC\n");
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goto unmap;
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}
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printk(KERN_INFO "OLPC board with OpenFirmware %.16s\n", romsig);
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olpc_platform_info.flags |= OLPC_F_PRESENT;
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/* get the platform revision */
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platform_detect();
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/* assume B1 and above models always have a DCON */
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if (olpc_board_at_least(olpc_board(0xb1)))
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olpc_platform_info.flags |= OLPC_F_DCON;
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/* get the EC revision */
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olpc_ec_cmd(EC_FIRMWARE_REV, NULL, 0,
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(unsigned char *) &olpc_platform_info.ecver, 1);
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/* check to see if the VSA exists */
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if (geode_has_vsa2())
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olpc_platform_info.flags |= OLPC_F_VSA;
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printk(KERN_INFO "OLPC board revision %s%X (EC=%x)\n",
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((olpc_platform_info.boardrev & 0xf) < 8) ? "pre" : "",
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olpc_platform_info.boardrev >> 4,
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olpc_platform_info.ecver);
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unmap:
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iounmap(romsig);
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return 0;
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}
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postcore_initcall(olpc_init);
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